The present invention relates to a process for making helmets for cyclists from foamed polyurethane.
A variety of helmets are known and widely used in different situations or places for protecting the head. The helmets for motorcyclists or cyclists are commonly made through a lot of complicated processing procedures, and therefore their manufacturing cost is high. Further, these helmets are commonly heavy and will make the head uncomfortable due to poor ventilation, motorcycle or bicycle riders are unwilling to wear them. In order to let motorcyclists or cyclists to wear a helmet while riding a motorcycle or bicycle, a lightweight safety helmet having good ventilation and high impact strength is needed.
Polyurethane has been known good for making a helmet being satisfactory in function. Polyurethane is any of various synthetic polymers produced by the polymerization of a hydroxyl (OH) radical and an NCO ground from two different compounds: used in elastic fibers, cushions, insulation, molded products, coatings, etc. Foamed polyurethane has been widely used for making insulating roof plates, packings for refrigerators and coolers and motor vehicles, mechanical spare parts for machinery and motor vehicles, etc., for the advantages of high elasticity and deformability, and high compression strength.
Through a specially designed production process, a satisfactory, lightweight safety helmet can be made from polyurethane. Because foamed polyurethane is highly deformable and can immediately return to its former shape after the external pressure has been released, it is a good way to use foamed polyurethane for making a safety helmet.
There are helmet manufacturers who use foamed polyurethane to make safety helmets for motorcyclists and cyclists by fastening a molded plastic outer shell to a molded inner shell of foamed polyurethane. This process is complicated.